Fluid flow control valves are well known. Typically a valve element is mounted in a valve opening provided in a valve housing and is rotatable between a closed position in which the valve element engages a valve seat provided around the valve opening and an open position in which the valve element disengages from the valve seat to allow fluid to flow through the valve opening.
Typically the valve element comprises a plate. However, with such a design, as the valve element rotates from the closed position to the open position, there is a rapid flow of fluid around the valve element and through the valve opening which may lead to a water hammer effect.
The present disclosure seeks to provide a valve construction which in certain embodiments at least may mitigate such effects.